Devices known as infusion catheters are commonly used to deliver a therapeutic treatment fluid such as a thrombolytic agent to a clot or other undesired tissue within a vein or artery in a patient. A wide variety of infusion catheter designs are known and commercially available. One conventional design includes a longitudinally extending fluid lumen within an infusion catheter body which connects a supply of treatment fluid positioned outside of the patient with an intraluminal space such as a vein or artery by way of effusion ports formed in the catheter body.
During certain infusion procedures, and notably procedures where a thrombolytic agent is used to dissolve or break up clot material within a vein or artery, pieces of the clot may become dislodged, potentially causing complications in a well known manner. A variety of filtration mechanisms are used to capture pieces of clot material or “emboli” such that the material can be removed from the patient, dissolved by a thrombolytic agent, or otherwise prevented from migrating to other regions of the patient's body.
In venous infusion procedures, a common filtration strategy involves implanting a filter within the vena cava of the patient, such that any emboli which migrate from an infusion site are prevented from entering the patient's heart or lungs. Vena cava filters of many different designs have been used successfully for years. One downside to their use, however, is that a semi-permanent filter is implanted within the patient, and typically must at some point be removed. This necessitates a subsequent interventional procedure. Other filter techniques utilize filters placed close to the infusion site, and often designed as integral parts of the infusion catheter itself or other interventional instruments. These conventional techniques too have their disadvantages.